Cell culture media support and maintain the growth of cells in an artificial environment.
Depending on the type of organism whose growth shall be supported, the cell culture media comprise a complex mixture of components, sometimes more than one hundred different components.
The culture media required for the propagation of mammalian, insect or plant cells are typically much more complex than the media to support the growth of bacteria and yeasts.
The first cell culture media that were developed consisted of undefined components, such as plasma, serum, embryo extracts, or other non-defined biological extracts or peptones. A major advance was thus made with the development of chemically defined media. Chemically defined media often comprise but are not exclusively limited to amino acids, vitamins, metal salts, antioxidants, chelators, growth factors, buffers, hormones, and many more substances known to those expert in the art.
Some cell culture media are offered as sterile aqueous liquids. The disadvantage of liquid cell culture media is their reduced shelf life and difficulties for shipping and storage. As a consequence, many cell culture media are presently offered as finely milled dry powder mixtures. They are manufactured for the purpose of dissolving in water and/or aqueous solutions and in the dissolved state are designed, often with other supplements, for supplying cells with a substantial nutrient base for growth and/or production of biopharmaceuticals from same said cells.
The production of cell culture media in the form of powders is very critical. Powdered media are typically produced by admixing the dried components of the culture medium via a mixing process, e.g., ball-milling, or by lyophilizing pre-made liquid culture medium. However, in a lyophilisation process some of the components of the medium might become insoluble or aggregate upon lyophilization such that resolubilization is difficult or impossible. Furthermore, when using a milling process, many of the ingredients used in culture media, e.g., L-glutamine and FBS, cannot be added to the culture medium prior to the milling process due to their sensitivity to shearing by processes such as ball-milling. Furthermore, many of these supplements, particularly serum supplements such as FBS, show a substantial loss of activity due to too much energy transfer (heat) or oxidation during milling. This leads to a decrease of the overall performance of the cell culture medium produced.
Consequently, there exists a clear need for finding an improved process for manufacturing powdered cell culture media that does not have the disadvantages mentioned above.